Laboratory

What happens in the IVF laboratory after fertilization

After fertilization the oocytes are cultivated in special culture mediums inside an incubator at a temperature of 37°C for 2-6 days.

Embryo cleavage stages:

Day 1

after fertilization - pre-nucleus stage

Day 2

after fertilization - 2 to 4-cell stage

Day 3

after fertilization - 6 to 8-cell stage

Day 4

after fertilization - morula stage

Day 6

after fertilization - blastocyst stage

Mediums for embryo culture

From a number of 3 oocytes, we use two different culture mediums at the same time to guarantee the best environment for embryonic cleavage.

The so-called "sequential culture medium" imitate the environment inside the fallopian tubes that surrounds the oocyte on their way to the uterine cavity. The medium we use after three days of cleavage has a different composition of nutrients.

The "global medium" stay the same for all five days of cleavage. The embryo can choose which nutrients he need in every cleavage stage.

It has not been clear yet why some embryos prefer a certain medium and others grow well in both types. It shall be assumed that there is a connection to the maternal age and other factors that are not known yet.